The present invention relates to a microlens array, a manufacturing method thereof, an optical device, and an electronic device.
Hitherto, microlens arrays in which a plurality of minute lenses are arranged have been used for, for example, liquid crystal panels. When using the microlens array, light entering each pixel is focused by each lens; hence, a bright display is achieved. Known methods for manufacturing the microlens array are dry etching and wet etching.
However, the above methods require a lithography process for each step of forming the individual microlens arrays, thus increasing the costs. As disclosed in Japanese Unexamined Patent Application Publication No. 3-198003, the following method for manufacturing a microlens array has been developed: a resin is dripped onto a master on which spherical (curved) surfaces corresponding to individual lenses are formed, and then the resulting resin is solidified and is detached.
A second light-transmitting layer composed of a resin having a refractive index different from the microlens array is generally formed above the microlens array, and a protective layer composed of glass or the like is formed above the second light-transmitting layer, if necessary. A black matrix, a transparent electrode layer, and an orientation film are further formed above the same, and this laminate is used for the opposing substrate of a liquid crystal panel.
The black matrix is formed using lithographic techniques. In detail, a light shield material such as Cr is deposited above the microlens array. Then, a resist layer is formed on the same, is patterned by performing exposure through a mask having a predetermined pattern, development is performing, and then the black matrix is provided by performing etching by using the patterned resist as a mask.
Since it is required to precisely form the black matrix between the lenses, the mask is aligned with the lenses when performing exposure.
Since precise alignment is required when forming the black matrix having high quality, there is a problem in that conventional microlens array manufacturing methods can not comply with this requirement.
It is an object of the present invention to provide a microlens array which can be precisely aligned with other members, a manufacturing method thereof, and an optical device.
A method for manufacturing a microlens array according to the present invention includes the steps of forming a reflecting layer as a mark in a first light-transmitting layer having a plurality of lenses and the mark composed of at least one of a raised part and a recessed part, the reflecting layer having a higher reflectance than that of the first light-transmitting layer; and
forming a second light-transmitting layer so as to cover at least the lenses.
The present invention provides a microlens array having a first light-transmitting layer having a plurality of lenses and a mark having at least one of a raised part and a recessed part formed, a reflecting layer which has a higher reflectance than that of the first light-transmitting layer being formed as the mark, and a second light-transmitting layer formed so as to cover at least the lenses.